package com.taotao.tools.codec.aes;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * @version V1.0
 * @desc AES 加密工具类
 */
public class AESUtil {

	private static final String PROJECT_DEFAULT_ENCODING = "UTF-8";

	private static final String KEY_ALGORITHM = "AES";
	/**
	 * //默认的加密算法
	 */
	private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";

	/**
	 * AES 加密操作
	 *
	 * @param content  待加密内容
	 * @param password 加密密码
	 * @return 返回Base64转码后的加密数据
	 */
	public static String encrypt(String content, String password) {
		try {
			// 创建密码器
			Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

			byte[] byteContent = content.getBytes(PROJECT_DEFAULT_ENCODING);

			// 初始化为加密模式的密码器
			cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(password));

			// 加密
			byte[] result = cipher.doFinal(byteContent);

			// 通过Base64转码返回
			return new String(Base64.encodeBase64(result), PROJECT_DEFAULT_ENCODING);
		} catch (Exception ex) {
			Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
		}

		return null;
	}

	/**
	 * AES 解密操作
	 *
	 * @param content
	 * @param password
	 * @return
	 */
	public static String decrypt(String content, String password) {

		try {
			// 实例化
			Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

			// 使用密钥初始化，设置为解密模式
			cipher.init(Cipher.DECRYPT_MODE, getSecretKey(password));

			// 执行操作
			byte[] result = cipher.doFinal(Base64.decodeBase64(content));

			return new String(result, PROJECT_DEFAULT_ENCODING);
		} catch (Exception ex) {
			Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
		}

		return null;
	}

	/**
	 * 生成加密秘钥
	 *
	 * @return
	 */
	private static SecretKeySpec getSecretKey(final String password) {
		// 返回生成指定算法密钥生成器的 KeyGenerator 对象
		KeyGenerator kg = null;

		try {
			kg = KeyGenerator.getInstance(KEY_ALGORITHM);

			// AES 要求密钥长度为 128
			kg.init(128, new SecureRandom(password.getBytes()));

			// 生成一个密钥
			SecretKey secretKey = kg.generateKey();

			// 转换为AES专用密钥
			return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);
		} catch (NoSuchAlgorithmException ex) {
			Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
		}

		return null;
	}

	public static void main(String[] args) {
		String s = "hello,您好";

		System.out.println("s:" + s);

		String s1 = AESUtil.encrypt(s, "1234");
		System.out.println("s1:" + s1);

		System.out.println("s2:" + AESUtil.decrypt(s1, "1234"));

	}

}